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A student wishes to investigate the effect of surface area on the rate of reaction between marble chips and hydrochloric acid. Which variables should he control?

Concentration of HCl, Mass of marble chips (use excess HCl).
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Answered by Alfie B. • Chemistry tutor
5058 Views

How is structure relevant to enzyme function?

Enzymes are functional proteins which are used to catalyse reactions. They all exhibit primary, secondary and tertiary structure, and some which have more than one polypeptide chain have quaternary structure...
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Answered by Alec M. • Biology tutor
28962 Views

Expand the following expression: -5x(x-7)(x+3)

Expansion of the given expression will result in x to the 3rd power, as there are 3 parts involving x, multiplied together. Let's ignore -5x for a second, and multiply the two expressions in brackets (using ...
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Answered by Matas S. • Maths tutor
5545 Views

The curve has equation y = x^3 - x^2 - 5x + 7 and the straight line has equation y = x + 7. One point of intersection, B, has coordinates (0, 7). Find the other two points of intersection, A and C.

As both equations are equal to y, we can combine them to create a single equation in terms of x: x^3 - x^2 -5X + 7 = x + 7. Shift the equation so the left hand side is equal to 0 on the right: x^3 - x^2 - 6x...
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Answered by Alfie B. • Maths tutor
7895 Views

Briefly outline the divisions and roles of the human nervous system.

The role of the nervous system is to collect, process and respond to information in the environment and to coordinate the workings of organs and cells in the body. It is subdivided into the central nervous s...
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Answered by Sammy L. • Psychology tutor
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